What are resins ? How are they useful?

Resin is a semi-fluid secreted by special tubes which contains terpenes, resin acids and esters.
(a) It solidifies on exposure to air. Therefore, it plugs the places of injury.
(b) It helps in sealing female cones after pollination.
© It retains water.
(d) It is antiseptic and toxic to pests.
(e) It is commercially extracted to obtain turpentine and resin.
(f) Resin is used in water proofing, sealing joints and preparation of writing paper.
(g) Turpentine is used as solvent in paints, polishes and wax.
(h) It is employed medicinally in removing pains, curing bronchitis and expelling worms.